EP 1040211 A1 20001004 - METHOD FOR PICKLING AND PASSIVATING SPECIAL STEEL
Title (en)
METHOD FOR PICKLING AND PASSIVATING SPECIAL STEEL
Title (de)
VERFAHREN ZUM BEIZEN UND PASSIVIEREN VON EDELSTAHL
Title (fr)
PROCEDE POUR LE DECAPAGE ET LA PASSIVATION D'ACIER SPECIAL
Publication
Application
Priority
- DE 19755350 A 19971212
- EP 9807866 W 19981203
Abstract (en)
[origin: DE19755350A1] The invention relates to a method for pickling and/or passivating special steel. The steel is brought into contact with an aqueous treatment solution with a pH value that is below or equal to 2.5 at a temperature of 30-70 DEG C. Said solution contains 15-110g/l ferrous ions. The inventive method is characterized in that the Fe (II) formed during the pickling process is oxidized into a trivalent state by bringing the treatment solution into contact with oxygen in the presence of 50 - 2000 mg/l copper (II) ions. The preferred copper concentration is 200-6000 mg/l. A pickling solution devoid of nitric acid and containing a mixture of sulphuric acid and hydrofluoric acid can, for instance, be used.
IPC 1-7
IPC 8 full level
C23G 1/08 (2006.01)
CPC (source: EP)
C23G 1/081 (2013.01); C23G 1/086 (2013.01)
Citation (search report)
See references of WO 9931296A1
Designated contracting state (EPC)
DE ES FR GB IT SE
DOCDB simple family (publication)
DE 19755350 A1 19990617; AR 010966 A1 20000712; AU 2157999 A 19990705; DE 59810931 D1 20040408; EP 1040211 A1 20001004; EP 1040211 B1 20040303; ES 2217621 T3 20041101; WO 9931296 A1 19990624; ZA 9811343 B 19990614
DOCDB simple family (application)
DE 19755350 A 19971212; AR P980106294 A 19981211; AU 2157999 A 19981203; DE 59810931 T 19981203; EP 9807866 W 19981203; EP 98965754 A 19981203; ES 98965754 T 19981203; ZA 9811343 A 19981210